Ice flux of Plogbreen, a small ice stream in Dronning Maud Land, Antarctica

Abstract

AbstractAs part of a long-term mass-balance program run by SWEDARP since 1988, a detailed study on Plogbreen, Dronning Maud Land, Antarctica, was undertaken during the austral summer of 2003 to investigate the long-term mass balance. We compare ice outflux, φout, through a cross-sectional gate with ice influx, φin, from the upstream catchment area. The φin is based on calculations of snow accumulation upstream of the gate using data available from published ice-core records. The φout is based on Glen’s flow law aided by thermodynamic modeling and force-budget calculations. Input data from the field consist of measurements of ice surface velocity and ice geometry. The ice surface velocity was measured using repeated differential global positioning system surveying of 40 stakes over a period of 25 days. The ice geometry was determined by 174 km of ground-penetrating radar profiling using ground-based 8MHz dipole antennas. This study presents the collected velocity and geometry data as well as the calculated ice flux of Plogbreen. The results show a negatively balanced system within the uncertainty limits; φout = 0.55 ± 0.05 km3 a–1 and φin = 0.4 ± 0.1 km3 a–1. We speculate that the negative balance can be explained by recent eustatic increase reducing resistive stresses and inducing accelerated flow.